The present embodiments relate to positioning a load.
During particle therapy, a particle beam, for example, including protons or heavy ions, is generated in an accelerator. The particle beam is carried in a radiation channel from the accelerator to an exit window of the radiation channel. The particle beam enters an irradiation or treatment room through the exit window. The particle beam may be used to treat cancer.
The success of tumor treatment depends on the precision of the tumor positioning. Positioning a patient depends on a plurality of factors. For example, the precision of positioning depends on how the patient is supported and the rigidity of the patient support system. In positioning the patient, the weight of the patient may cause elastic deformation that leads to imprecise positioning.
A more-rigid construction may be used to avoid elastic deformation under the load of the patient. However, the more-rigid construction results in higher costs.
Alternatively, it is possible to compensate for elastic deformation, for example, by using known load data to compensate for a predictable deformation. The system cannot be used flexibly, since the load data have to be known prior to treatment. In particle therapy, the load data is not known because of the variability of the loading from one patient to another.
Another possibility is to use sensors, such as force-torque sensors, to ascertain the loading. However, such systems are comparatively expensive.